The following information is provided to assist the reader in understanding technologies disclosed below and the environment in which such technologies may typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technologies or the background thereof. The disclosure of all references cited herein are incorporated by reference.
Personal Mobility Devices (PMDs) such as electronic power wheelchairs (EPW) as illustrated in FIG. 1A, scooters as illustrated in FIG. 1B and manual wheelchairs as illustrated in FIG. 1C are very beneficial to the people with mobility impairments. As used herein, the term “personal mobility device” or PMD refers to mobile devices to transport a person, thereby increasing the mobility of the person. However, those benefits come with some risks. One such risk lies in the stability of the PMD. A review of the US Food and Drug Administration's (FDA's) Manufacturer and User Facility Device Experience (MAUDE) database shows that one of the most frequent adverse events connected to these devices is their inclination to tip; causing the user to be thrown from the device and injured, sometimes severely. In a study done between 1975 and 1993, 25.7% of the wheelchair safety incidents reported to the FDA were from a tip and/or fall. R. Lee Kirby, S. A.-S. Wheelchair Safety-Adverse Reports to the Food and Drug Administration, American Journal of Physical Medicine and Rehabilitation, 308-312 (1995).
To help prevent these injuries the US Department of Veterans Affairs (VA), the FDA and the Centers for Medicare & Medicaid Services (CMS) require that PMDs are tested for stability issues and that the results then be published in the user manual. Testing the PMDs and reporting the results do not necessarily mean that they are stable. However, the VA has become more proactive about requiring that PMDs be more stable. They have indicated in their requests for low cost EPW's that they are dynamically stable on a 6° slope.
It is a good idea to change the design of the PMDs to make them more stable; however any design change may affect the performance of the device as well. Slowing the speed of the device reduces mobility and independence. Making a wider frame can limit access to narrow places. Stiff suspension reduces user comfort. Passive anti-tip devices limit some safe maneuvers and can be ineffective if not properly adjusted to the user's specifications.